This study is to evaluate the effects of chronic nonpulsatile systemic blood flow in alive, awake animals. Previously, it was believed that pulsatile blood flow was required for the maintenance of normal organ function. This concept, however, was based on acute studies and on low flow states in most cases. The function of both right and left hearts can be replaced by two nonpulsatile pumps draining blood from the atrium and ventricle and returning to the appropriate artery. To avoid competition with the beating heart, the ventricles are maintained in a state of continuous fibrillation. The initial studies have shown that up to 93 days, an animal can maintain normal organ function with nonpulsatile blood flow provided adequate pressure and flow is maintained. In this grant, the effects of varying nonpulsatile blood flow will be assessed, and in addition, more prolonged studies of nonpulsatile blood flow for periods up to six months will be evaluated.